Heat transfer device



y F. 5. SLAGEL 1,869,174 I HEAT TRANSFER DEVICE Filed April 17. 1930 .u i fl 4 H 2 a Z a Patented July 2 6, 1932 UNITED STATES PATENT OFFICE FRANKLIN G. SLAGEL, OF BUFFALO, NEw YORK, ASSIGNOR TO FEDDEBS IAN'UI'AG'I.'U'R- ING COMPANY, INC., 01 BUFFALO, NEW YORK, A CORPORATION OF NEW YORK I HEAT runsran DEVICE Application filed April 1?, 1980. Serial No. 445,120;

This invention relates to heat transfer devices, and is particularly useful in refrigerating and heating systems.

An object of the invention is to provide an indirect heat transfer structure which is light in weight, rugged and of a wall area which is large compared to the over all di mensions.

Another object of the invention is to-provide an indirect heat transfer structure formed of light plates which are designedand arranged to permit airflow in a horizontal and vertical direction therethrough.

A further object of my invention is to provide an evaporator structure formed of tubes and metal sheets which will present a large wall area through which air can circulate in a plurality of directions and in contact with substantially the entire plate surfaces. Still another object of the invention is to rovide an indirect heat transfer structure 1n which plates are formed with a large area occupying a relatively small space, and all points of which are relatively close to the circulating medium.

Another object of the'invention is to pro vide an evaporator for refrigerating systemswhich includes an indirect heat transfer area of a character formed and arranged so that there will be no frosting.

Other objects of the invention will appear from the following description taken in connection with the drawing, which form a part of the specification, and in which:

Fig. 1 is aside elevational view of an evaporator. I

Fig. 2 is an end view of the same.

- Fig. 3 is a fragmentary plan view of the same. i

Figs. 4 and 5 are sectional views of two forms of plates which compose the fin portion of the evaporator.

Referring now to the drawing by characters of reference, 9 and, 10 represent two connected headers of an evaporator structure forming a part of a mechanical refrigerating system. A conduit 11 connects the lower header with a condenser (not shown), while conduits 12 extend from the upper header to the compressor (not shown). The passage of refrigerant into the lower header is controlled by the conventional float valve when a flooded system is desired, or the entrance of the refrigerant into the header can be controlled by an expansion valve when a dry system is desired. Such controls are well known in the art and need no further explanation here.

A plurality of tubes 13 extend laterally from the header 10 and with one end in open communication with the interior of the header. It will be understood that the tubes can be arranged to project from the header in various planes, in which eventit may be necessary to arrange the inlet. and outlet differently than shown. Tubes 7 connect the header 9 with the as space in the header 10, while a common tu e connection joins the extended ends of each vertical row of tubes 13 and each connection 8 is in communication with the header 9 through a tube 6. An oil conduit 5 has an open end in the header 10' and leads to one of the outlet conduits 12 so that section removes the oil asfast as it accumulates on the body of liquid refrigerant in the header when the flooded system is employed. A conduit 4 servesto j om the tube 5 with the outlet conduit.

This invention has to do with the association of fins with a tube structure, of the character described, to present a non-frosting, indirect heat transfer surface which materially increases the surface of contact without the increase of the over all dimension.

The desired result is accomplished through the use of two forms of plates 15 and 16 which are associated in rows with the tubes in any number that may be desired to produce the indirect wall surface needed. The plates are preferably formed of thin sheets of alumimum in order to produce a structure which is light in weight and at the same time have a rate of heat transfer. The two types of plates are substantially the same in form, except for the manner of arranging the edge portions on two sides. A central portion 17 and two intermediate portions 18 of each platevare maintained in their original form,

-which is flat, while the portions between the central and intermediate portions are slit at regularly spaced intervals. The portiors intermediate the slits are pressed out on opposite sides alternately and in the form of angular walls 19 and with the connecting portions 20 form hexagonal flues, when looking at the structure in plan. Such flues are indicated by the numeral 21.

The portions 22 of the plates'15 adjacent the outer edges of the portions 18 are bent at similar angles, only extending in directions toward the adjacent edges of the plates. The portions 23 of the plates 16, adjacent the outer edges of the portions 18 are bent similar to the portions 22of the plates 15 only from the opposite side. The edged portions of the plates extend parallel to the portions 17 and 18 respectively, and in alignment with .the portions 19, such portions being indicated by the numeral 24:. The plate edge'portions 24 are relieved asat 25 for the purpose appearing hereinafter, the relieved portions forming the major part of the edge portions.

The central portions of the plates are provided with flanges 26 forming apertures through which the legs or tubes 6 and 13 are projected before final assembly with the header, and the fin structure can consist of as many sets and rows of plates as maybe desired. The fins are pressed onthe tubes and are secured thereto by dipping in solder.

A plate of each type, as shown in Figs. 4

Y and 5, are assembled to form a set, and are arranged on the tubes so that the edge portions 22 and 23 project toward each other in abutting relation intermediate the relieved portions. The adjacent contacting surfaces of the plates are only the small unrelieved edge portions 24, the plates being entirely spaced otherwise. The portions 19 and 20 of the adjacent plates in each set provide verticallv extending hexagonal flues 21, as before explained. and those portions of the plates between the hexagonal flues 21 and the portions 17 of adjacent plates form larger vertically extending fiues 29 therebetween.

Looking from on top of the fin structure,

I each row-of sets of fins appear comprised of a plurality of hexagonal flues, while looking plates, it can travel horizontally both longifrom the side atthe fin structure, as shown in Fig. 1, the complementary relieved surfaces 25 provide horizontally extending elongated fiues 30, and similar spaces extend between each set of plates, only alternately in two planes. as defined bv the wall portions 19 and 20 forming horizontal flues 31. Air can circulate horizontally through the slits in the .lows a plurality of fin structure sizes to be formed with only the two types of plates, the major portions of which can be formed in the same manner which facilitates manufacturing economy.

Although this invention has been described in connection with a certain specific embodiment, the principles involved are susceptible of numerous other applications which will readily appear to persons skilled in the art, and the invention is therefore to be limited only as indicated by the scope of the appended claims.

What I claim is 1. A fin for indirectly transferring heat comprising a sheet of metal having two parallel intermediate portions provided with spaced slits and bent outwardly therefrom alternately on opposite sides forming parallel fines. and having opposite edges bent outwardly therefrom on the same side, the fin portion between the parallel portions having a tube opening therethrough.

2. In a heat transfer structure, a plurality of sheet metal plates each having a fiat central portion formed with parallel rows of slits there n. the portions between the slits in each row being similarly bent out alternately on opposite sides of the central portion of the plates. and liquid conducting tubes extending in intimate contact with the plates intermediate the fines formed by the bent out portions and perpendicular thereto.

3. In a heat transfer structure, a plurality of sheet metal plates arranged in a row and having rows of spaced similarly arranged slits therethrough, the portions between the slits each being bent out similarly and alternately in each row on opposite sides of each plate forming a pair of parallel fiues on each plate, the bent out portions of adjacent plates extending in the same direction relatively,

and liquid conducting tubes extending in intimate contact with the plates intermediate the fiues and perpendicular thereto.

, 4. In a heat transfer structure, a plurality of sheetmetal plates formed in similar pairs, the plates of each pair being formed with parallel rows of slits with the slits in each slightly out of register. the portions between the slits in each plate being similarly bent out alternately on opposite sides and slightly overlapping the bent out portions of the adjacent plate lengthwise of the rows, and liquid conducting tubes extending in'intimate contact with the plates intermediate the flues formed by the bent out portions and perpendicular thereto.

5. In a heat transfer structure, a plurality of sheet metal plates formed in similar pairs, said plates having similar rows of slits therethrough and the portions between the slitsbent out similarly and on opposite sides, the ends of each pair of plates being bent toward each other to form flues therebetween exterior of the slitted portions, and liquid conducting tubes extending in intimate contact with the plates intermediate the slitted bent out portions.

In testimony whereof I afiix my signature. FRANKLIN G. SLAGEL. 

